156 CLASS IV. 



Cidaris KLEIN, Cidarites LAM. (Cidaris, Diadema, Astropyga 

 GRAY, AG-ASS.) Ambulacra parallel. Tubercles sustaining the 

 spines not perforate, often remarkable for their size. 



Sp. Cidaris vcrticillata, GUE'R. Iconogr. Zooph. PI. 3, fig. I ; in the Indian 

 Sea, on the coasts of Timor, &c. Of this genus many fossil species also 

 are known. 



Family IV. Holotkuridea. Body free, mostly cylindrical, 

 covered with a coriaceous skin, furnished with calcareous particles 

 scattered, reticulate. Mouth surrounded by retractile tentacles. 

 Anus terminal, opposite to the mouth (Genus Holothuria L. exclu- 

 sive of several species). 



Comp. on this family : 



G. J. JAEGER De Holothuriis, Dissertatio inaug. Turici, 1833, 4to. 

 cum tab. J. F. BRANDT Prodromus descriptionis animalium ab 

 H. MERTENSIO in orbis terrarum circumnavigations observatorum. 

 Fasc. i. Petropoli, 1835, 4 to. pp. 42 62, GRUBE Actinien, JEchino- 

 dermen und Wurmer des Adriatischen und Afittlemeers, Konigsb. 

 1840, 4to. pp. 33 42. There are many figures of European 

 ffolothurice in the Zoologia danica and of foreign species in LESSON 

 Centurie Zoologique, Paris 1830, 8vo. 



We have spoken above (p. 140) of the calcareous ring which may 

 be considered as a vestige of a skeleton, and which serves for the 

 attachment of the longitudinal muscles. The pieces of which this 

 ring consists are toothed above, but they do not discharge the office 

 of teeth, the food, as far as it undergoes separation and mastication 

 previous to deglutition, being thus effected by the callous skin 

 surrounding the mouth alone. Holothurice feed upon conchifera and 

 other marine animals ; TIEDEMANN frequently found shells entire and 

 uninjured in the intestinal canal of Holothuria tubulosa, so that the 

 molluscs appeared to have been dissolved in the shell and digested. 

 The bits of shell and the other matters unfit for use and undigested 

 are rejected from the cloaca with the water in expiration. We 

 have indicated above the chief particulars respecting the internal 

 structure. 



See, besides, TIEDEMANN 1. 1., also the beautiful engraving from a prepara- 

 tion by HUNTER in Catalogue of the Physiolog. Series of Compar. Anat. 

 contained in the Museum of the Royal College of Surgeons, Vol. I. London, 

 1833, PL m - PP- 250254. 



The numerous species of this family are separated according 

 to the form of the Tentacles (LAMARCK, GRUBE), the position of the 



